Understanding RAM usage on Linux

Posted by stebbo on Super User See other posts from Super User or by stebbo
Published on 2011-06-24T08:12:01Z Indexed on 2011/06/24 8:24 UTC
Read the original article Hit count: 137

Filed under:

linux

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java

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memory-management

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tomcat

I'm completely new to Linux and I'm just trying to understand where all my RAM is going. I've got a pretty fresh install of Xubuntu running as a VMWare guest, and I've given it 1.5GB RAM to play with.

After only running two apps starting up Tomcat servers and also running Firefox, I've got hardly anything left. 160MB according to free -m.

Looking at the output from Top, I see Java appearing twice, each stealing about 1/2 Gig resident memory. Both Tomcat instances use the same jdk, I would have thought I'd only see Java there once.

What's the story? I had a screenshot but unfortunately couldn't post it being under 10 rep.

Update

The free -m output requested:

             total     used     free    shared    buffers    cached
Mem:          1419     1380       39         0          8       111
-/+ buffers/cache:     1259      160       
Swap:          509       68      441

Top (coming)

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